THE STUDY OF UNCINARIASIS OF THE SEA LION ON THE REPRODUCTIVE ROOKERY OF TYULENY ISLAND

Abstract

On Tyuleny Island, the largest reproductive rookery of the sea lion is located that is formed by migratory specimens. The research purpose was to study the spread of uncinariasis in sea lions and to determine its infection rates. The studies were conducted from June 20 to August 12, 2021. The carcasses of dead cubs were collected on the western beach (WPL) in the area of sites 10, 11, and 12. The dead animals were subjected to helminthological dissection taking into account the recommendations for the collection of helminthological material from marine mammals. A comparative analysis of the recorded number of cubs allowed us to detect a trend to its increase. During the period of field studies, 2382 puppies were recorded including 2195 alive, and 187 dead specimens. In comparison with 2020, the number of young animals increased by 258 individuals, but the invasion prevalence also increased by 2.8%. The epizootic process had age and seasonal dynamics. The cause of death of puppies in the first days after birth were injuries and exhaustion. Mortality from uncinariasis according to preliminary data was recorded in cubs aged 15-30 days. The average rate of invasion intensity per specimen was 2004.2±325.7 specimens (937–4360). No significant differences between the sex groups were detected.